This is all very interesting. The question is, do any current ABS systems
use accelerometers? If so, which ones?
(sorry to butt in)
Matt Pringle had this to say:
>Even on ice the car will be slowing (albeit extremely slowly).
>Acceleromters can be extremely sensitive.
>
>Matt
>
>Bob Howard wrote:
>>
>> Matt,
>> I can follow your logic if the skid is on pavement where at least one
>> wheel has good grip. If all four wheels were on ice, how would it sense
>> deceleration?
>> Bob
>>
>> On Fri, 21 Jan 2000 08:43:47 -0500 Matt Pringle <pringlmm@mcmaster.ca>
>> writes:
>> > Actually sensing the difference between being stopped and skidding
>> > with
>> > all wheels locked is very simple and I'd be very surprised if they
>> > don't
>> > do it already. When you're skidding, you're still slowing down and
>> > so
>> > an accelerometer could easily sense this.
>> >
>> > Matt
>> >
>> > Chris Kotting wrote:
>> > >
>> > > Paul -
>> > >
>> > > Aha! You've discovered ABS's weak point. Allow me to ask a
>> > question:
>> > > How does ABS know that a wheel is locked? Think about this for a
>> > second
>> > > before reading the next line.
>> > >
>> > > Ready for the answer?
>> > >
>> > > By comparing rotional speeds of the four wheels.
>> > >
>> > > Now for the next question: How can an ABS system tell the
>> > difference
>> > > between these two states (a) all four wheels locked and sliding,
>> > and (b)
>> > > stopped?
>> > >
>> > > Answer? It can't.
>
--
Max Heim
'66 MGB GHN3L76149
If you're near Mountain View, CA,
it's the red one with the silver bootlid.
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